A Massachusetts nominee trust is (a) in writing, (b) has one or more persons or corporations named as trustees, (c) has an identified corpus, (d) has beneficiaries identified on a written schedule held by the trustees but not disclosed to the public, and (e) contains various trustee powers as to corpus dispositions that can only be exercised when authorized by the beneficiaries.
The beneficiaries are the owners of the corpus for all purposes, including income, gift and estate taxation, except being the owners of record of the corpus. There is a Principal/Agent relationship between the Trustees and the Beneficiaries, and it is somewhat the reverse where usually in a Grantor Trust, the Trustee instructs the Beneficiaries on what he will/is allowed to do for them, but in a Nominee Trust the Beneficiaries direct the Trustee.
The nominee trust was conceived as an estate-planning vehicle to allow a decedent's real estate to pass to beneficiaries without the necessity of it being probated, e.g., the undisclosed beneficiaries would be also be the trustees of the Nominee trust (you can't have the same trustee be the only beneficiary, but the same two trustees can be the same two beneficiaries!)
The trustees have liability in tort but not in contract if the trust has appropriate language stating that those dealing with the trust may look only to trust property when a dispute arises with the trustee and giving the trustee ostensible authority to deal with the trustee.
